Numerous studies have reported beta-hydroxynitrosamines, as well as their oxo derivatives to be metabolites of nitrosamines in vivo and in vitro. Beta-Hydroxynitrosamines can be produced in the environment from a wide variety of ubiquitous beta-hydroxyamines. It has been proposed elsewhere that beta-ketonitrosamines undergo biochemical fragmentation to simpler nitrosamines which eventually alkylate nucleic acids. Previous work in these laboratories has led to the discovery of a facile chemical cleavage of beta-hydroxy and beta-acetoxynitrosamines. Here we propose to elucidate the chemical fragmentation reactions of beta-hydroxy, beta-keto, and beta-acetoxynitrosamines and delta-ketonitrosamines (possible products of environmental tertiary amine nitrosation) by examining the response of the rate and extent of cleavage to structural features and the nature of catalysts in order to perceive the role that such transformations may play in the environmental production and destruction of nitrosamines in relation to their carcinogenicity and as a model for a biochemical study. A search for the biochemical counterparts to the foregoing transformations as well as a determination of the respective biochemical roles of beta-hydroxy- vs. beta-ketonitrosamines is also proposed in order to further elucidate the mechanisms of nitrosamine carcinogenesis. The examination of the possible addition of nucleophiles to enenitrosamines to produce fragmentable substances is also a part of this proposal as is the exploration of the fragmentation of oxidation products of beta-hydroxynitrosamines which could produce nitrogen containing metabolites. Further understanding of the relationship of these processes to nitrosamine carcinogenesis will be sought by utilization of the Ames Mutagen Assay to screen compounds.